This invention relates generally to flow rate detection systems, and, more particularly to a halogen mass flow rate detection system which can be readily incorporated within a chemical laser.
Recent studies on chemical laser systems, and in particular oxygen/iodine chemical lasers have indicated a need for an accurate, diagnostic system for determining the amount of iodine (I.sub.2) being injected into the laser or resonant cavity. Knowledge of the iodine mass flow rate is essential in an understanding of the operation of such a chemical laser. This is because the excited oxygen/iodine ratio is extremely critical in the operation of the laser, in that either too little or too much iodine will cause the efficiency of the laser to drop drastically.
The present method of injection of iodine within the resonant cavity consists of passing an inert gas such as argon over a container of heated iodine (60.degree. C.), thus entraining some unknown density of iodine therein. This mixture is then passed into a slit nozzle for subsequent mixing with excited oxygen.
There are well-established techniques for measuring the amount of excited oxygen entering the laser but there are no techniques capable of accurately measuring the mass flow rate of iodine. A measurement of the temperature of the iodine container does not give a reliable iodine density reading because of the nonequilibrium situation; i.e., a saturated vapor pressure above the iodine crystals is not achieved because of the rapid flow of the argon or inert gas carrier. Hence, one cannot even be certain that higher argon flow rates lead to higher iodine density being injected into the laser.
As pointed out hereinabove a determination of the mass flow rate of iodine is essential to proper chemical laser operation. More specifically, too much iodine will cause the so-called ".sup.1 .SIGMA. catastrophe" where the kinetics of the oxygen-iodine system are altered to such an extent that the laser will not operate. Too little iodine causes the extractable power to drop. In addition, knowledge of the iodine mass flow rate greatly aids in the modeling of laser systems.
It is therefore readily apparent from the above recitation that an iodine mass flow rate detection system or, more generally, a halogen flow rate detection system is extremely desirable, and is of utmost importance in, for example, the utilization of chemical lasers.